Non-aqueous cell having amorphous or semi-crystalline copper manganese oxide cathode material

ABSTRACT

The present disclosure relates generally to a high capacity cathode material suitable for use in a non-aqueous electrochemical cell that comprises copper manganese oxide, which may be in amorphous or semi-crystalline form, and optionally fluorinated carbon. The present disclosure additionally relates to a non-aqueous electrochemical cell comprising such a cathode material and, in particular, to such a non-aqueous electrochemical cell that can deliver a higher capacity than conventional cell.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority from U.S. Provisional PatentApplication No. 61/112,562 (filed Nov. 7, 2008), No. 61/161,303 (filedMar. 18, 2009), No. 61/161,300 (filed Mar. 18, 2009), and No. 61/173,534(filed Apr. 28, 2009), the entire contents of each being incorporatedherein by reference.

FIELD OF THE DISCLOSURE

The present disclosure relates generally to a high capacity cathodematerial suitable for use in a non-aqueous electrochemical cell thatcomprises an amorphous or semi-crystalline form of copper manganeseoxide, and optionally fluorinated carbon. The present disclosureadditionally relates to a non-aqueous electrochemical cell comprisingsuch a cathode material and, in particular, to such a non-aqueouselectrochemical cell that can deliver a higher capacity thanconventional cell.

BACKGROUND OF THE DISCLOSURE

Lithium electrochemical cells, which are more commonly referred to asbatteries, are widely used in a variety of military and consumerproducts. Many of these products utilize high energy and high powerbatteries. Due in part to the miniaturization of portable electronicdevices, it is desirable to develop even smaller lithium batteries withan increased power capability and service life. One way to developsmaller batteries with increased service life is to develop higherenergy cathode materials.

One example of a high energy cathode material is fluorinated carbon(i.e., CF_(x)). CF_(x) is often used with a lithium anode innon-rechargeable (primary) batteries for, among other things, militarydevices and implantable medical devices. CF_(x)(where x=1.0) has aspecific energy of about 860 mAh/g. Other examples of high energycathode materials include silver vanadium oxide and manganese dioxide,which have specific capacities of about 315 and 308 mAh/g, respectively.

The cathodes for rechargeable (secondary) batteries, such as Li ionbatteries, generally have lower energy storage capability than primarybattery cathodes. However, secondary batteries can typically berecharged several hundred times, which significantly reduces thelifetime cost as well as the battery disposal costs. Examples ofsecondary battery cathodes used in Li ion batteries include lithiumcobalt oxide, lithium iron phosphate, and lithium nickel cobalt oxide.

To satisfy the demands for longer lasting or smaller batteries, therecontinues to be a need to develop cathodes exhibiting higher energy likeprimary batteries with the possibility of partial or fully rechargeablecapability like secondary batteries, thus extending lifetime andeffectively reducing the overall cost. Mixed cathode materials have beenproposed as one possible approach for achieving such improved primaryand/or secondary batteries. Other benefits of mixed cathode materialsinclude enhancing the rate capability and/or stability of the cathode,while maintaining the energy density per weight and/or per volume.Approaches for achieving such benefits have typically involved mixing ahigh rate-capable cathode material with a high energy-density cathodematerial.

U.S. Pat. No. 7,476,467 discloses a cathode material for secondarylithium batteries. The cathode active material comprises a mixture of(A) a lithium manganese-metal composite oxide having a spinel structure.and (B) a lithium nickel-manganese-cobalt composite oxide having alayered structure. The cathode active material is said to have superiorsafety and a long-term service life at both room temperature and hightemperature due to improved properties of lithium and the metal oxide.

It is known to those skilled in the art that composite cathodescomprising fluorinated carbon with some other metal oxide are used forthe purpose of providing the battery with an end-of-life (EOL)indicator. For example, U.S. Pat. No. 5,667,916 describes a batteryhaving a cathode mixture of CF_(x) and other materials, including forexample copper oxide, the other material or mixtures of other materialsserving as the end-of-life indicator. Similarly, U.S. Pat. No. 5,180,642discloses electrochemical cells or batteries having a cathode mixturecomprised of manganese dioxide (MnO₂), carbon monofluoride (CF_(X),where x=1), or mixtures of the two, and an end-of-life additive selectedfrom the group consisting of vanadium oxide, silver vanadate, bismuthfluoride and titanium sulfide. U.S. Pat. No. 4,259,415 provides acathode material as an end-of-life indicator comprising a main positiveactive material and a precursor. Suitable main positive active materialsinclude molybdenum oxide (MoO₃), silver oxide (Ag₂O), and graphitefluoride (CF)_(n).

Although many batteries or cells developed to-date include end-of-lifeindicators, the energy density is less than desired. The capacity (e.g.mAh/gm or mAh/cc) of the EOL additive to CF_(x) (for example, silvervanadium oxide, or SVO) is lower than that of the CF_(x) material,resulting in a composite electrode with a total capacity lower than thatof the CF_(x) by itself. Additionally, or alternatively, many batteriesor cells developed to-date exhibit an initial voltage sag or drop at thebeginning of the discharge. Therefore, a need continues to exist forimproved cells, and more particularly for improved cathode materials foruse in such cells.

SUMMARY OF THE DISCLOSURE

Briefly, therefore, the present disclosure is directed to a non-aqueouselectrochemical cell. The cell comprises: (i) an anode; (ii) a cathodecomprising a cathode material comprising copper manganese oxide; (iii) aseparator disposed between the anode and the cathode; and, (iv) anon-aqueous electrolyte which is in fluid communication with the anode,the cathode and the separator.

The present disclosure is further directed to such a non-aqueouselectrochemical cell wherein the copper manganese oxide has the formulaCu_(a)Mn_(b)O_(c), wherein (i) the copper therein has an oxidation statebetween about 1 and about 3, (ii) the manganese therein has an oxidationstate between about 2 and about 7, (iii) a and b each have a valuegreater than zero, and further that the sum of a+b is between about 1and about 3; and, (iv) c has a value greater than zero that may beexperimentally determined and that is consistent with the values of a, band the oxidation states of copper and manganese. More particularly, thepresent disclosure is directed to such a non-aqueous electrochemicalcell wherein copper manganese oxide is amorphous, the copper andmanganese being present therein in an average molar ratio of about 1:1to less than 3:1. Alternatively, the present disclosure is directed tosuch a non-aqueous electrochemical cell wherein copper manganese oxideis semi-crystalline, the copper and manganese being present therein inan average molar ratio of 3:1 to about 6:1.

The present disclosure is still further directed to one of the foregoingnon-aqueous electrochemical cells, wherein the cathode materialadditionally comprises fluorinated carbon.

The present disclosure is still further directed to one of the foregoingnon-aqueous electrochemical cells, wherein the cell is internallyrechargeable.

The present disclosure is still further directed to one of the foregoingnon-aqueous electrochemical cells, wherein the composition and/or formof the copper manganese oxide, and optionally the ratio thereof relativeto fluorinated carbon in the cathode material in the cell, provides animproved end-of-life indicator, as compared to a similarly preparedcathode material in the absence of the copper manganese oxide.

The present disclosure is still further directed to various electronicdevices comprising such an electrochemical cell.

It is to be noted that one or more of the additional features detailedbelow may be incorporated into one or more of the above-notedembodiments, without departing from the scope of the present disclosure.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 illustrates a first exemplary test cell for testing variousembodiments of the present disclosure.

FIG. 2 illustrates an x-ray diffraction graph according to an embodimentof the copper manganese oxide cathode material of the presentdisclosure.

FIG. 3 illustrates a discharge voltage profile according to a furtherembodiment of the copper manganese oxide (Cu_(a)Mn_(b)O_(c)) cathodematerial of the present disclosure.

FIG. 4 illustrates discharge voltage profiles according to yet anotherembodiment of the copper manganese oxide (Cu_(a)Mn_(b)O_(c))/CF_(x)(15/85) cathode material of the present disclosure, versus a sample ofCF_(x) alone.

FIG. 5 illustrates cyclic voltammograms according to other embodimentsof the present disclosure.

FIG. 6 illustrates a lithium CF_(x) discharge profile.

FIG. 7 illustrates a lithium CF_(x) discharge profile.

FIG. 8 is a table showing the density of various Cu_(a)Mn_(b)O_(c)samples, the density being a function of the annealing temperature,according to various embodiments of the disclosure.

FIGS. 9 and 9A illustrate schematic drawings of a coin cell used fortesting various alternative embodiments of the present disclosure, FIG.9A being a schematic cross-section of the cell if FIG. 9 along line 9A.

FIG. 10 illustrates the density of cathode materials formed inaccordance with various embodiments of the present disclosure(Cu_(a)Mn_(b)O_(c)), and in particular illustrating the change indensity as a function of Cu:Mn molar ratio.

FIG. 11 illustrates an x-ray diffraction graph for cathode materialsformed in accordance with various embodiments of the present disclosure,and in particular illustrating the change as a function of Cu:Mn molarratio.

FIGS. 12A and 12B illustrates Scanning Electron Microscopic images ofcathode material formed in accordance with various embodiments of thepresent disclosure.

FIGS. 13A (XPS-Cu) and 13B (XPS-Mn) illustrates x-ray photonspectroscopic results of cathode materials formed in accordance withvarious embodiments of the present disclosure.

FIG. 14 illustrates thermal decomposition of cathode materials formed inaccordance with various embodiments of the present disclosure, and inparticular the change as a function of Cu:Mn molar ratio.

FIG. 15 illustrates a discharge voltage profile of a cell formedaccording to a further embodiment of the present disclosure (the Cu:Mnmolar ratio of the cathode material therein being 3:1).

FIG. 16 illustrates a discharge voltage profile of a cell formedaccording to yet another embodiment of the present disclosure.

FIG. 17 illustrates a discharge profile of a cell formed according toyet another embodiment of the present disclosure.

FIG. 18 illustrates voltage profiles for ICD testing on LiCF₁,Li/CF_(x), and Li/(CF_(x)+Cu_(a)Mn_(b)O_(c)) cells in accordance withvarious embodiments of the present disclosure.

DETAILED DESCRIPTION OF THE DISCLOSURE 1. Cathode Material Compositionand Cell Components

In accordance with the present disclosure, and as further detailedherein below, it has been discovered that one or more performanceproperties of a non-aqueous electrochemical cell may be improved orenhanced by the use of a cathode material comprising copper manganeseoxide, and more particularly amorphous or semi-crystalline coppermanganese oxide. In one particular embodiment of the present disclosure,it has been further discovered that performance of such a non-aqueouscell may be improved or enhanced when copper manganese oxide, and moreparticularly amorphous or semi-crystalline, is used in combination withfluorinated carbon (i.e., CF_(X)).

In this regard it is to be noted that, as used herein, “non-aqueous”refers to an electrochemical cell that comprises or utilizes an organicsolvent, or a mixture of organic solvents, in combination with aninorganic or organic salt, as an electrolyte. Accordingly, thenon-aqueous electrolyte contains no added water; that is, water was notadded to the electrolyte as a separate or distinct component thereof,but nevertheless may be present as a trace or underlying component orcontaminant of the organic solvent(s) used to prepare it. For example,in one or more non-limiting embodiments of the present disclosure, theelectrolyte may typically have a water content of less than about 1000ppm, about 750 ppm, about 500 ppm, about 250 ppm, about 100 ppm, about50 ppm, about 25 ppm, about 20 ppm, or even less.

In this regard it is to be further noted that an electrochemical cellmay otherwise be referred to herein as a battery, a capacitor, a cell,an electrochemical device, or the like. It should be understood thatthese references are not limiting, and any cell that involves electrontransfer between an electrode and an electrolyte is contemplated to bewithin the scope of the present disclosure.

In this regard it is to be still further noted that “improved” or“enhanced” performance properties generally refers to an improvement orenhancement in the specific energy, the energy density, the operatingvoltage, the rate capability, and/or the end-of-life behavior orindicator of the non-aqueous electrochemical cell of the presentdisclosure, as compared for example to a non-aqueous electrochemicalcell that is similarly prepared or design but that lacks the coppermanganese oxide cathode material as detailed herein.

The copper manganese oxide cathode material of the present disclosuremay generally be represented by the formula Cu_(a)Mn_(b)O_(c), and inone or more particular embodiments may be represented by the formulaCu_(a)Mn_(b)O_(c).nH₂O, wherein “nH₂O” represents the structural and/orsurface water present in the cathode material. In the cathode material,copper may have an oxidation state between about +1 and about +3, andmanganese may have an oxidation state between about +2 and about +7.Additionally, a, b and c each independently have a value of greater than0, and furthermore (i) the sum of a+b may be in the range of from about1 to about 3, while (ii) c has a value that may be experimentallydetermined and that is consistent with the values of a, b and theoxidation states of copper and manganese, and in one or more embodimentsis a value such that copper has an oxidation state of approximately +2or higher.

In this regard it is to be noted that the copper manganese oxide of thepresent disclosure is not crystalline (e.g., it does not have aspinel-type structure, as is generally known in the art). Rather, thecopper manganese oxide of the present disclosure is amorphous, oralternative semi-crystalline, in form. The amorphous or semi-crystallinenature of the material is believed to be, at least in part, a functionof the molar ratio of copper to manganese. In particular, among thevarious embodiments of the present disclosure are those wherein theamorphous copper manganese oxide has the formula Cu_(a)Mn_(b)O_(c),wherein the average molar ratio of Cu to Mn is about 1:1 or more, theratio for example being between about 1:1 and less than (about) 3:1(Cu:Mn), or between about 1.25:1 and less than about 2.75:1 (Cu:Mn), orbetween about 1.5:1 and less than about 2.5:1 (Cu:Mn). In variousalternative embodiments, wherein the copper manganese oxide issemi-crystalline and has the formula Cu_(a)Mn_(b)O_(c), the averagemolar ratio of Cu to Mn is (about) 3:1 or more, the ratio for examplebeing between (about) 3:1 and about 6:1 (Cu:Mn), or between about 3.25:1and about 5.75:1 (Cu:Mn), or between about 3.5:1 and about 5.5:1(Cu:Mn).

Additionally, it is to be noted that the amorphous or semi-crystallinecopper manganese oxide cathode material of the present disclosure mayadvantageous having an average density of about 4 g/cm³, about 4.5g/cm³, about 5 g/cm³, about 5.5 g/cm³, about 6 g/cm³ or more (thedensity ranging for example from about 4 g/cm³ to about 6 g/cm³, orabout 4.5 g/cm³ to about 4.5 g/cm³). Additionally, or alternatively, thecathode material may have a surface area (as determined using meansgenerally known in the art, including for example the BET method) of atleast about 50 m²/g, of at least about 75 m²/g, about 100 m²/g, about125 m²/g, about 150 m²/g , or more, and in one or more embodiments mayhave a BET surface within the range of, for example, about 50 to about150 m²/g, or about 75 to about 125 m²/g. In this regard it is to befurther noted that the surface area, and thus the ranges related theretothat are noted herein, is a function of the conditions under which thematerial was prepared, and therefore should not be viewed in a limitingsense.

In addition to the copper manganese oxide cathode material detailedherein, the other components of the non-aqueous electrochemical cell maybe selected from among those generally known in the art. For example,according to various embodiments of the present disclosure, the cathodemay also include a binder, for example, a polymeric binder such aspolytetrafluoroethylene (PTFE) or polyvinylidene fluoride (PVDF), whichmay optionally be in powdered form. Additionally, carbon materials suchas carbon black (e.g., Super P, from Timcal), natural and syntheticgraphite, as well as their various derivatives (including graphene,graphite nano platlets, expanded graphite—such as KS4, from Timcal),carbon nano-fibers, and non-graphitic forms of carbon, such as coke,charcoal or activated carbon, may be used as conductive fillers in thecathodes.

In one particular embodiment, however, the cathode material of thepresent disclosure additionally comprises a carbonaceous activematerial, and includes graphitic material such as natural and syntheticgraphite and all their derivatives including graphene, graphitenano-platelet, expanded graphite, carbon nano-fiber and nongraphiticforms of carbon such as coke, charcoal or activated carbon. In onepreferred embodiment, the carbonaceous material is preferably preparedfrom carbon and fluorine (i.e., it is a fluorinated carbon material).The fluorinated carbon material may generally be represented by theformula (CF_(x))n, wherein x typically varies between about 0.1 to 1.9,preferably between about 0.4 and 1.2, and more preferably between about0.6 and 1.0. The fluorinated carbon can also be a mixture of (CF_(x1))nand (CF_(x2))m, where x1 is preferably about 0.8 to 1.2, and x2 ispreferably about 0.4 to 0.8. In this regard it is to be noted that inthe formulas (CF_(x))n and (CF_(x1))n, as well as (CF_(x2))m, n and mrefer to the number of monomer units which can vary widely, but may befor example within the range of about 1 to about 5. Accordingly, theratio of (CF_(x1)) to (CF_(x2)) may be, for example, between about 5:1and about 1:5, about 4:1 and about 1:4, or about 3:1 and about 1:3, orabout 2:1 and about 1:2, or even a ratio of about 1:1; stated anotherway, the cathode material of the present disclosure, in variousembodiments, may contain a mixture of CF_(x), such as for example amixture of CF₁/CF_(0.6), wherein the mixture has contains for exampleabout 90% CF₁ and about 10% CF_(0.6), or about 80% CF₁ and about 20%CF_(0.6), or about 75% CF₁ and about 25% CF_(0.6), or about 67% CF₁ andabout 33% CF_(0.6), or about 50% CF₁ and about 50% CF_(0.6), or viceversa.

It is to be noted that the precise composition of the copper manganeseoxide, and/or the precise composition of the fluorinated carbon, and/orthe respective concentrations of copper manganese oxide and/orfluorinated carbon, present in the cathode material may be optimized fora given application or use, by means generally known in the art. Forexample, in one particular embodiment, one or more of these factors maybe controlled or optimized in order to improve or enhance theend-of-life behavior of the electrochemical cell. More specifically, oneor more of these factors may be controlled or optimized in order toensure that the electrochemical cell possess or exhibits a voltageplateau after some period of use or discharge, which may act as a usefulend-of-life indicator. In this regard it is to be further noted that thedischarge voltage of fluorinated carbon is typically between about 2.5volt (V) and about 2.8V, depending on the discharge rate. In contrast,the copper manganese oxide material of present disclosure exhibits avoltage plateau between about 2 or about 2.3V and about 2.4V, asillustrated for example in FIG. 3.

As used herein, “voltage plateau” generally refers to a portion of thedischarge curve that is substantially or relatively flat, within thenoted voltage range, for some measurable or detectable period (e.g.,over some measurable range of specific capacity values). This voltageplateau is well-suited as end-of-life indicator for a fluorinatedcarbon/copper manganese oxide non-aqueous electrochemical cell, inaccordance with the present disclosure. The amount (i.e., concentrationand/or ratio), composition, and/or form of the copper manganese oxideand fluorinated carbon can be optimized to give the desire end-of-lifebehavior for different applications (the concentrations or ratios ofthese two cathode materials, for example, having an effect on thespecific capacity range at which or over which this plateau isobserved).

The respective concentrations of copper manganese oxide and/orfluorinated carbon present in the cathode material may be optimized fora given application or use, by means generally known in the art. In oneparticular embodiment, however, the cathode mixture of the presentdisclosure may comprise from between about 1% and about 99%, by weight,of the fluorinated carbon, and in some instances may comprise frombetween about 10% and about 98%, or about 20% and about 97%, or about40% and about 96%, or about 60% to about 95%, and in some embodimentsmay be between about 65% to about 90%, or about 70% to about 85%, byweight. Additionally, the cathode mixture may comprise from betweenabout 1% and about 99%, by weight, of the copper manganese oxide, and insome instances may comprise from between about 2% and about 90%, orabout 3% and about 80%, or about 4% and about 60%, or about 5% and about40%, and in some embodiments may be between about 10% and about 35%, orabout 15% and about 30%, by weight. In this regard it is to be notedthat, in some embodiment, wherein the cathode material comprises coppermanganese oxide and fluorinated carbon, the cathode material may consistessentially of these components; that is, the sum of the concentrations(or weight percents) of the copper manganese oxide and fluorinatedcarbon may be about 100%. However, in this regard it is to be noted thatsuch concentrations should not be viewed in a limiting sense. Forexample, in various alternative embodiments, the copper manganese oxidemay be the major component of the cathode material (rather than forexample the fluorinated carbon).

It is also to be noted that, among the various embodiments of thepresent disclose, are included those wherein the cathode material isnon-lithiated. Stated another way, the cathode material is prepared suchthat, at least initially (i.e., prior to use), the cathode material isessentially free of lithium or lithium ions therein (i.e., lithium orlithium ions are not intentionally added as a component of the cathodematerial during preparation). In one particular embodiment, the cathodematerials consists essentially of copper manganese oxide, fluorinatedcarbon, and optionally a binder material and/or a conductive additive(both as further detailed elsewhere herein below). For example, in onepreferred embodiment, the cathode material comprises or consistsessentially of, by weight, about 81% of the fluorinated carbon and about12% of the copper manganese oxide, about 3% binder material, and about4% conductive additive. However, such cathode materials may be utilizedin an electrochemical cell with a lithium (Li) anode, for primary(non-rechargeable) or secondary (rechargeable) batteries. As a result,in use, lithium or lithium ions may be present in such a cathodematerial. The presence of such lithium or lithium ions in use shouldtherefore not be viewed in a limiting sense.

Without being held to any particular theory, it is to be noted that thecombination of copper manganese oxide and fluorinated carbon is believedto be particularly advantageous because the combination of thesecomponents yields a material having surprisingly higher capacity thanexpected, based on the individual capacities of the copper manganeseoxide and fluorinated carbon. Stated another way, as further illustratedelsewhere herein, the capacity of this mixed cathode material has beenobserved to be higher than the sum of the individual capacities of thecopper manganese oxide and fluorinated carbon alone.

The electrochemical cell of the present disclosure additionallycomprises an anode, which may essentially comprise any anode materialsuitable for use in non-aqueous electrochemical cells. Typically,however, the anode comprises a metal selected from Group IA or Group IIAof the Periodic Table of the Elements, including for example lithium,magnesium, sodium, potassium, etc., and their alloys and intermetalliccompounds, including for example Li—Mg, Li—Al, Li—Al—Mg, Li—Si, Li—B andLi—Si—B alloys and intermetallic compounds. The form of the anode mayvary, but typically it is made as a thin foil of the anode metal, and acurrent collector having an extended tab or lead affixed to the anodefoil.

As previously noted, the electrochemical cell of the present disclosurefurther includes a non-aqueous, ionically conductive electrolyte, whichserves as a path for migration of ions between the anode and the cathodeelectrodes during the electrochemical reactions of the cell. Theelectrolyte can be in either liquid state or solid state, or both. Theelectrochemical reaction at the electrodes involves conversions of ionsin atomic or molecular forms that migrate from the anode to the cathode.Thus, non-aqueous electrolytes suitable for the present disclosure aresubstantially chemically inert to the anode and cathode materials.Furthermore, a suitable electrolyte in liquid state exhibits thosephysical properties that are beneficial for ionic transport (e.g., lowviscosity, low surface tension, and/or good wettability).

The various components of the electrolyte may be selected from amongthose generally known in the art, which are suitable for use incombination with the cathode materials detailed elsewhere herein.Preferably, however, a suitable electrolyte for use in accordance withthe present disclosure has an inorganic or organic, ionically conductivesalt dissolved in a non-aqueous solvent (or solvent system, when amixture of solvents is used). More preferably, the electrolyte includesan ionizable alkali metal salt dissolved in an aprotic organic solventor a mixture of solvents comprising a low viscosity solvent and a highpermittivity solvent. Without being held to any particular theory, theinorganic, ionically conductive salt is believed to serve as the vehiclefor migration of the anode ions to react with the cathode activematerial. Accordingly, preferably the ion-forming alkali metal salt issimilar to the alkali metal comprising the anode.

In one particular embodiment of the present disclosure, for theelectrolyte, the ionically conductive salt preferably has the generalformula MM′F₆ or MM′F₄, wherein M′ is an alkali metal that is the sameas at least one of the metals in the anode and M′ is an element selectedfrom the group consisting of phosphorous, arsenic, antimony and boron.Salts suitable for obtaining the formula M′F₆ include, for example,hexafluorophosphate (PF₆), hexafluoroarsenate (AsF₆) andhexafluoroantimonate (SbF₆), while salts suitable for obtaining theformula M′F₄ include, for example, tetrafluoroborate (BF₄).Alternatively, the corresponding sodium or potassium salts may be used.Thus, for a lithium anode, the alkali metal salt of the electrolyte mayoptionally be selected from, for example, LiPF₆, LiAsF₆, LiSbF₆ andLiBF₄, as well as mixtures thereof. Other salts that are useful with alithium anode include, for example, LiClO₄, LiAlCl₄, LiGaCl₄,LiC(SO₂CF₃)₃, LiB(C₆H₄O₂)₂, LiN(CF₃SO₂)₂ and Li(CF₃SO₃), as well asmixtures thereof.

Low-viscosity solvents that may be suitable for use in accordance withthe present disclosure in the electrochemical cell include, for example:dimethyl carbonate (DMC), diethyl carbonate, 1,2-dimethoxyethane (DME),tetrahydrofuran (THF), methyl acetate (MA), diglyme, trigylme,tetragylme, and high permittivity solvents, include for example cycliccarbonates, cyclic esters and cyclic amides (such as propylene carbonate(PC), ethylene carbonate (EC), acetonitrile, dimethyl sulfoxide,dimethyl formamide, dimethyl acetamide, gamma-butyrolactone (GBL), andN-methyl-pyrrolidinone (NMP)), as well as various mixtures orcombinations thereof.

The type and composition of the solvent used in the electrolyte, and/orthe type and concentration of a salt present therein, may be selected inorder to optimize one or more physical and/or performance properties ofthe electrochemical cell of the present disclosure. For example, in oneor more embodiments of the present disclosure, the concentration of thesalt in the electrolyte may be in the range of from about 0.5M to about2.5M, or from about 0.75M to about 2.25M, or from about 1M to about 2M.In these or other embodiments of the present disclosure, wherein a mixedsolvent system is employed, the ratio (volume) may range for examplefrom between about 1:9 and about 9:1 of a first solvent (e.g., acarbonate solvent, such as propylene carbonate) and a second solvent(e.g., a substituted alkane solvent, such as 1,2-dimethoxyl ethane);that is, the solvent system may comprises from about 10 volume % toabout 90 volume %, or from about 20 volume % to about 80 volume %, orfrom about 30 volume % to about 70 volume %, of a first solvent, all orsubstantially all of the balance of the solvent system being the secondsolvent. In one preferred embodiment, however, the anode is lithiummetal and the preferred electrolyte is 1.0M to 1.8M LiBF₄ in a mixedPC/DME solvent system (the concentration of the solvent system beingbetween about 10 volume % PC/90 volume % DME and about 70 volume % PC/90volume % DME).

The electrochemical cell of the present disclosure additionallycomprises a suitable separator material, which is selected to separatethe cathode/cathode material from the Group IA or IIA anode/anodematerial, in order to prevent internal short circuit conditions. Theseparator is typically selected from materials known in the art to beelectrically insulating (and sometimes ionically conductive), chemicallynon-reactive with the anode and cathode active materials, and bothchemically non-reactive with and insoluble in the electrolyte. Inaddition, the separator material is selected such that it has a degreeof porosity sufficient to allow flow through of the electrolyte duringthe electrochemical reaction of the cell. Finally, the separatormaterial is typically selected to have a thickness ranging from, forexample, about 15 microns to about 75 microns, or about 20 microns toabout 40 microns.

Accordingly, suitable separator materials typically include, or may beselected from, porous or nonporous polymer membranes, such as forexample: polypropylene, polyethylene, polyamide (e.g., nylon),polysulfone, polyvinyl chloride (PVC), and similar materials, andcombinations thereof (e.g., a trilayer membrane, such as a trilayermembrane of polypropylene/polyethylene/polypropylene), as well asfabrics woven from fluoropolymeric fibers, including for examplepolyvinylidine fluoride (PVDF), polyvinylidinefluoride-cohydrofluorpropylene (PVDF-HFP), tetrafluoroethylene-ethylenecopolymer (PETFE), chlorotrifluoroethylene-ethylene copolymer, andcombinations thereof. Fabrics woven from these fluoropolymeric fiberscan be used either alone or laminated a microporous film (e.g., afluoropolymeric microporous film).

The form or configuration of the electrochemical cell of the presentdisclosure may generally be selected from those known in the art. In oneparticular embodiment, however, the form or configuration of theelectrochemical cell is a case-negative design, wherein thecathode/anode/separator/electrolyte components are enclosed in aconductive metal casing such that the casing is connected to the anodecurrent collector in a case-negative configuration, althoughcase-neutral design is also suitable. A preferred material for thecasing is titanium, although stainless steel, nickel, and aluminum arealso suitable. The casing header comprises a metallic lid having asufficient number of openings to accommodate the glass-to-metalseal/terminal pin feed through for the cathode electrode. The anodeelectrode is preferably connected to the case. An additional opening isprovided for electrolyte filling. The casing header comprises elementshaving compatibility with the other components of the electrochemicalcell and is resistant to corrosion. The cell is thereafter filled withthe electrolyte solution described hereinabove and hermetically sealed,such as by welding a stainless steel plug over the fill hole. In thisregard it is to be noted, however, that the cell of the presentdisclosure may alternatively be constructed in a case-positive design.Accordingly, the description provided herein should not be viewed in alimiting sense.

In this regard it is to be further noted that other components of theelectrochemical cell (e.g., current collectors, etc.) may be selectedfrom among those components generally known in the art, withoutdeparting from the scope of the present disclosure.

Once the cathode material has been prepared, it may be deposited on thecathode current collector in the form of single, substantiallyhomogenous mixture (e.g., wherein copper manganese oxide particulate isdispersed into CF_(x) particulate, or vice versa, depending on which isthe major component and which is the minor component of the cathodematerial, and then this mixture is deposited in the form of a singlelayer on the cathode current collector). Alternatively, however, when amixture of cathode components or materials are used, these materials maybe deposited in the form of layers on (i) the same side of the currentcollector (e.g., a layer of copper manganese oxide deposited on thesurface of the current collector, then a layer of CF_(x) is deposited onthe copper manganese oxide layer, or vice versa), or (ii) the oppositesides of the current collector.

It is to be noted that, unless otherwise stated, the variousconcentrations, concentration ranges, ratios, etc. recited herein, areprovided for illustration purposes only and therefore should not beviewed in a limiting sense. It is to be additionally noted that allvarious combinations and permutations of compositions, concentrations,ratios, components, etc. are intended to be within the scope of andsupported by the present disclosure.

2. Cathode Material Preparation

The copper manganese oxide cathode material may be prepared by meansgenerally known in the art, involving for example the chemical reactionof various copper and manganese salts or oxides of both metals, eitherby solid state reactions or by wet chemistry (including, for example,thermal treatment, sol-gel formation, and hydrothermal synthesis inmixed states).

However, in one or more particular embodiments, the copper manganeseoxide material may be prepared in a way that provides or yields thematerial in an amorphous or semi-crystalline form or state. For example,such copper manganese oxide material may be prepared by aco-precipitation process in the presence or absence of an oxidizingagent, such as potassium persulfate or potassium perchlorate, of coppersalts and manganese salts, by a precipitating agent such as potassiumhydroxide or sodium carbonate. Alternatively, the cathode material maybe the product of the thermal decomposition of copper salts andmanganese salts in an appropriate environment. By controlling, forexample, the molar ratio of copper to manganese in the startingmaterials, such that the average molar ratio of copper to manganese inthe copper manganese oxide reaction product is within the ranges detailsherein above, the copper manganese oxide reaction product may beamorphous or semi-crystalline, or a combination or mixture thereof.

Once prepared, the resulting copper manganese oxide may be obtained inthe form of particulate (either directly, or after a milling or grindingstep of some kind) having an average particle size ranging from about 10nanometers to about 300 nanometers, or from about 50 nanometers to about225 nanometers, or from about 80 nanometers to about 150 nanometers.Optionally, the particulate may be agglomerated to form largerparticles, having for example an average particle size of ranging fromabout 5 microns to about 45 microns, or from about 7.5 microns to about30 microns, or from about 10 microns to about 15 microns.

3. Electrochemical Cell Uses and Performance Properties

It is to be noted that the precise composition of the copper manganeseoxide, and/or the cathode material (e.g., mixture of copper manganeseoxide with CF_(X)), may be selected to optimize it for a desiredperformance property, and/or the desired end-use application of theelectrochemical cell containing it. Additionally, it is to be noted thatit is anticipated within the present disclosure that many other cathodematerials may similarly benefit from the addition of Cu_(a)Mn_(b)O_(c),forming a hybrid cathode therewith. Accordingly, references to CF_(x)should not be viewed in a limiting sense.

The cathode material of the present disclosure is generally suitable foruse in essentially any non-aqueous electrochemical cell known in theart. Additionally, such an electrochemical cell of the presentdisclosure, which contains the noted cathode material, is generallysuitable for a number of know applications or devices, including forexample: medical devices (such as pace makers, defibrillators, cardiacmonitors, drug delivery systems, pain management systems, etc.),portable military electronic devices (such as radios, transponders,weapon sights, etc.), marine devices (such as sonobuoys, torpedoes,etc.), aerospace devices (such as deep space probes, command destructsystems, back-up power systems, etc.), military and commercial sensors,remote data collection systems, among other known applications anddevices. Such a cathode material, and more specifically theelectrochemical cell containing it, may be particularly advantageous foruse in devices requiring end-of-life indicators (e.g., medical devices)due to the voltage plateau the cell posses (as further illustratedelsewhere herein below) during the latter portion of the capacity.

In one particular embodiment, the non-aqueous electrochemical cell ofthe present disclosure may be configured as a reserve battery or cell,whereby the non-aqueous electrolyte is maintained separately from theelectrodes, increasing the useful storage period of the battery over awide temperature range. When needed, the non-aqueous electrolyte andelectrodes may be automatically brought into contact, allowing thebattery to function in a normal manner.

The cathode materials of the present disclosure, and the non-aqueouselectrochemical cells comprising them, may additionally possess one ormore other performance properties that are similar to, if not improvedor enhanced as compared to, other materials and cells generally known inthe art. For example, in various embodiments electrochemical cells orbatteries that include a cathode comprising a Cu_(a)Mn_(b)O_(c) cathodematerial have been observed to exhibit a capacity that is substantiallysimilar to, if not greater than, other high energy cathodes currently inuse, such as CF_(x). For example, in one or more embodiments of thepresent disclosure, the cathode material of the present disclosure mayenable such a cell to produce more than about 800, about 900, about1000, about 1100 milliamp-hours per gram (mAh/g) or greater capacity atroom temperature. In comparison to the cathode material of the presentdisclosure, a cell comprising a CF_(x) cathode material may provideabout 820 mAh/g at room temperature. In other various embodiments,however, an electrochemical cell comprising the cathode material of thepresent disclosure may exhibit improved or enhanced specific energy,energy density, operating voltage, and/or rate capability, as comparedfor example to conventional non-aqueous electrochemical cells that usecathode materials that do not include copper manganese oxide as thecathode material.

Additionally, and as previously noted, Cu_(a)Mn_(b)O_(c) cathodematerial may also exhibit increased density compared to other highenergy cathodes, and therefore provide a higher energy density thancompeting materials, such as CF_(x). Exemplary densities of differentmaterials are illustrated in FIGS. 8 and 10. However, it should beappreciated that the density may, in accordance with various aspects,vary depending on the process conditions by which the material wasprepared (e.g., annealing temperature).

It is to be further noted that, in another particular embodiment of thepresent disclosure, the non-aqueous electrochemical cell may exhibitinternal charging or rechargeability; that is, the Cu_(a)Mn_(b)O_(c)cathode material of the present disclosure may exhibit the ability to atleast partial charge or recharge when used in the non-aqueouselectrochemical cell of the present disclosure. Specifically, it hasbeen observed that when electrochemical cells or batteries using such acathode material, and specifically a cathode material comprisingCu_(a)Mn_(b)O_(c) and CF_(x), were left at open circuit during alife-time test, which took several weeks, the cells exhibited anincreasing open cell voltage over time. Furthermore, upon subsequentdischarge, the total capacity of the cell exceeded theoreticalexpectations. Accordingly, the cathode material of the presentdisclosure exhibited an unexpected benefit, that being an internalrecharge behavior without the use of an external power source of anykind.

The potential for at least partial internal charging or internalrechargeability, in addition to the very high primary energy, also makeselectrochemical cells or batteries according to embodiments of thepresent disclosure uniquely-suited, for example, for use in a number ofdifferent types of devices. For example, such cells may be well-suitedfor use in implantable medical devices (e.g., pace makers).Alternatively, such cells may be used in devices designed for both fortraining and operational situations. An example is military or lawenforcement radios that must be used for short periods of time intraining, as well as long periods of operational or combat periods. Suchdevices generally utilize two different types of batteries: short liferechargeable batteries for training, and long life primary batteries forcombat. Cu_(a)Mn_(b)O_(c) enhanced batteries may provide a benefit ofcombining both functions in a single unit, thereby enhancingperformance, logistics, and cost savings.

In this regard it is to be noted that, as used herein, “internalcharging” or “internal recharging”, as well as variations thereof,generally refers to the ability of the Cu_(a)Mn_(b)O_(c) cathodematerial, when used in the non-aqueous electrochemical cell of thepresent disclosure, to recover or re-establish at least a portion of itsinitial capacity, without the application of an external energy sourceof some kind to do so.

Without being held to any particular theory, it is believed that theinternal charging or recharging mechanism of an electrochemical cell orbattery comprising a Cu_(a)Mn_(b)O_(c)/CF_(x) cathode material of thepresent disclosure may be described by the following set of reactions:

During Discharge Of The Battery:

At the Anode:

Li→Li⁺ +e  (1)

At the Cathode (Cu_(a)Mn_(b)O_(c)/CF_(x)/other oxides):

CF_(x) +xLi⁺ +xe→C+xLiF  (2)

CuO+2Li⁺+2e→Li₂O+Cu  (3)

Cu_(a)Mn_(b)O_(c) +nLi⁺ +ne→Li_(n)Cu_(a)Mn_(b)O_(c)  (4)

Mn_(b)O_(C) +mLi⁺ +me→Li _(m)Mn_(b)O_(c)  (5)

Self-Charging or Internal Recharging at the cathode:

2LiF+2Cu→CuF₂+2e+2Li⁺  (6)

Mn_(b)O_(C) +me+mLi⁺→Li_(m)Mn_(b)O_(c)  (7).

The CuF₂ is an attractive cathode material, which can deliver a specificcapacity of about 537 mAh/gm. CuF₂ may be electrochemically formed fromLiF and Cu in a non-aqueous electrolyte, through an intermediate, asillustrated below:

4LiF+Cu

Li₂CuF₂+2Li⁺+2e  (8).

It is to be further noted that, in another particular embodiment of thepresent disclosure, the non-aqueous electrochemical cell may exhibitimproved end-of-life behavior. More specifically, in one particularembodiment the composition (e.g., ratio of copper to manganese) and/orform of the copper manganese oxide (e.g., amorphous orsemi-crystalline), and optionally the ratio or concentration thereofrelative to the fluorinated carbon in the cathode material in the cell,enables the electrochemical cell to possess an improved end-of-lifeindicator, as compared to a similarly prepared cathode material in theabsence of the copper manganese oxide, the cell for example exhibiting,during discharge, a distinct secondary voltage plateau that is less thana first distinct voltage plateau, which acts to single the approachingend-of-life of the cell. Exemplary end-of-life behavior is furtherillustrated in one or more Examples, below (see, e.g., FIG. 3 and thediscussion related thereto).

Having described the disclosure in detail above, it will be apparentthat modifications and variations are possible without departing fromthe scope of the disclosure defined in the appended claims.

The following non-limiting examples are provided to further illustratethe various details and embodiments of the present disclosure.

EXAMPLES Example 1

Cu_(a)Mn_(b)O_(c) was prepared as follows:

CuSO₄.5H₂O (0.25 moles) and MnSO₄.H₂O (0.25 moles) were dissolved in anappropriate amount of deionized water to form a solution. About 100grams of potassium hydroxide solution (20%) were added drop-wise to thestirred solution of copper and manganese sulfate. The resultingprecipitate was collected by filtration and thoroughly washed withdeionized water, and dried at 60° C. for about 24 hours. The driedmaterial was then placed in an oven and heated in air at approximately250° C. for about 15 hours. Finally, the product was ground using mortarand pestle and sieved through a sieve of 60-micron mesh.

Example 2

Cu_(a)Mn_(b)O_(c) was prepared as follows:

CuSO₄.5H₂O (0.05 moles) and MnSO₄.H₂O (0.05 moles) were dissolved in anappropriate amount of deionized water to form a solution. Then, theresulting solution was added drop-wise to stirred solution of 20% KOHcontaining KClO₄ (0.0125 moles), which is used as an oxidizing agent.When the addition of the solution was completed, the reaction mixturewas stirred for about 4 hours. The resulting precipitate was filteredand washed thoroughly and deionized with water. The material was driedat approximately 60° C. for about 24 hours. Prior to being used as acathode active material, the dried sample was heat-treated atapproximately 250° C. for up to 24 to 72 hours, or at about 400° C. forapproximately two hours. Optionally, the dried sample may beheat-treated at approximately 250° C. for about 15 hours.

Example 3

CuSO₄.5H₂O (0.05 moles), MnSO₄.H₂O (0.05 moles) and K₂S₂O₈ (0.0125moles) were dissolved in an appropriate amount of deionized water toform a solution. Then, the resulting solution was added drop wise to astirred solution of 20% KOH. When the procedure was completed, theprecipitate was aged at room temperature in mother liquor for about 4hours while stirring. The aged precipitate was filtered and washedthoroughly with deionized water. The material was dried at about 60° C.for approximately 24 hours. Prior to being used as a cathode activematerial, the dried sample was heat-treated at approximately 250° C. forup to 24 to 72 hours, or at about 400° C. for approximately two hours.Optionally, the dried sample may be heat-treated at approximately 250°C. for about 15 hours.

Example 4

Cu_(a)Mn_(b)O_(c) was prepared as follows:

CuSO₄.5H₂O (1.5 moles) and MnSO₄.H₂O (0.25 moles) were dissolved in anappropriate amount of deionized water to form a solution. About 100grams of potassium hydroxide solution (20%) were added drop-wise to thestirred solution of copper and manganese sulfate. The resultingprecipitate was collected by filtration and thoroughly washed withdeionized water, and dried at 60° C. for 24 hours. The dried materialwas then placed in an oven and heated in air at approximately 250° C.for about 15 hours. Finally, the product was ground using mortar andpestle and sieved through a sieve of 60-micron mesh.

It is to be noted that Cu_(a)Mn_(b)O_(c) materials from precursorscontaining different Cu:Mn molar ratios other than 6:1 can be preparedusing the above described method.

Example 5

Cu_(a)Mn_(b)O_(c) was prepared as follows:

CuSO₄.5H₂O (1.5 moles) and MnSO₄.H₂O (0.25 moles) were dissolved in anappropriate amount of deionized water to form a solution. Then, theresulting solution was added drop-wise to stirred solution of 20% KOHcontaining KClO₄ (0.125 moles), which is used as an oxidizing agent.When the addition of the solution was completed, the reaction mixturewas stirred for about 4 hours. The resulting precipitate was filteredand washed thoroughly and deionized with water. The material was driedat approximately 60° C. for 24 hours. Prior to being used as a cathodeactive material, the dried sample was heat-treated at approximately 250°C. and 400° C. for about 15 and 2 hours, respectively.

It is to be noted that Cu_(a)Mn_(b)O_(c) materials from precursorscontaining different copper to manganese molar ratios other than 6:1 canbe also prepared using the above described method.

Example 6

CuSO₄.5H₂O (1.5 moles), MnSO₄.H₂O (0.25 moles) and K₂S₂O₈ (0.0125 moles)were dissolved in an appropriate amount of deionized water to form asolution. Then, the resulting solution was added drop wise to a stirredsolution of 20% KOH. When the procedure was completed, the precipitatewas aged at room temperature in mother liquor for about 4 hours whilestirring. The aged precipitate was filtered and washed thoroughly withdeionized water. The material was dried at about 60° C. forapproximately 24 hours. Prior to being used as a cathode activematerial, the dried sample was heat-treated at approximately 250° C. and400° C. for about 15 and 2 hours, respectively.

Example 7

CuSO₄.5H₂O (1.5 moles), MnSO₄.H₂O (0.25 moles), C₈H₈O₇ (2 moles) andK₂S₂O₈ (0.0125 moles) were dissolved in an appropriate amount ofdeionized water to form a solution, which has a pH of about 1.3. Then,20% KOH solution was added drop wise to the stirred solution until thepH of about 13 was reached, at which point precipitation of product iscomplete. When the procedure was completed, the precipitate was aged atroom temperature in mother liquor for about 45 minutes while stirring.The aged precipitate was filtered and washed thoroughly with deionizedwater. The material was dried at about 60° C. for approximately 24hours. Prior to being used as a cathode active material, the driedsample was heat-treated at approximately 250° C. and for about 15 hours.The corresponding copper to manganese molar ratio was 6:1.

Example 8

A sample of Cu_(a)Mn_(b)O_(c) was prepared as set forth in Example 7,except the copper to manganese molar ratio was 5:1 in the mixturesolution.

Example 9

A sample of Cu_(a)Mn_(b)O_(c) was prepared as set forth in Example 7,except the copper to manganese molar ratio was 4:1 in the mixturesolution.

Example 10

A sample of Cu_(a)Mn_(b)O_(c) was prepared as set forth in Example 7,except the copper to manganese molar ratio was 3:1 in the mixturesolution.

Example 11 Test Cell

A first exemplary test cell was constructed to illustrate thecharacteristics of a cathode that comprises Cu_(a)Mn_(b)O_(c), asprepared in Examples 1-3, above. With reference to FIG. 1, an exemplarytest cell comprises a housing X7, an anode X1, a cathode X3, a separatorX5 and a non-aqueous electrolyte was prepared. The cell may be usedeither as a rechargeable or non-rechargeable electrochemical cell. Inthe cell, the anode X1 was configured to be in electrical contact with anegative lead X2, a cathode X3 was configured to be in electricalcontact with a positive lead X4, a separator X5 was configured toelectrically separate anode X1 and cathode X3, and an electrolytepermeated the separator X5. Anode X1, cathode X3, separator X5 and theelectrolyte were configured to be contained within housing X7. One endof housing X7 was closed with a cap X6, and an annular insulating gasketor O-ring X8 was configured to provide a gas-tight and fluid-tight seal.Positive lead X4 was configured to connect cathode X3 to cap X6.

An electrochemical cell according to various embodiments may be of anyconfiguration, such as a cylindrical wound cell, a button or coin cell,a prismatic cell, a rigid laminar cell or a flexible pouch, envelope orbag cell.

Example 12 Analysis/Testing of Cu_(a)Mn_(b)O_(c) Using Test Cell

X-ray analysis that was performed on a 250° C. heat-treated CuMnOmaterial of Example 3 described above revealed an amorphous structure asillustrated in FIG. 2 (the distinct or sharp peaks or signals at about30, 36, 38, 44, 54, 58, 64, 68, 72, 76, 76, 81, 84 and 88 beingPDF-related peaks). A similar structure was obtained on the sample thatwas heat-treated at about 400° C. for approximately 2 hours.

The electrochemical behavior of the Cu_(a)Mn_(b)O_(c) of Example 3 wasevaluated in a pouch cell, constructed consistent with the detailsprovided above, using lithium metal as an anode. The cathode consistedof 70% Cu_(a)Mn_(b)O_(c) as active material, 14% Super P carbon and 8%KS4 graphite as conductive fillers, and 8% PVDF as binder.Cu_(a)Mn_(b)O_(c), Super P and KS4 were first mixed through ballmilling. Then the resulting dry mix was added to a PVDF dissolved inN-methyly-2-pyrrolidene (NMP) solution to form a slurry. Finally, theslurry was applied on a carbon coated aluminum foil substrate to form acathode, using an electrode coater equipped with an oven to evaporatethe NMP.

FIG. 3 shows the discharge profile of the Example 3 Cu_(a)Mn_(b)O_(c)cathode material discussed above in a pouch cell using lithium metal asan anode. The measurements were carried out at room temperature undergalvanostic conditions, at a discharge rate of 10 milliamp per gram(mA/g) of cathode active material. The discharge capacity to 1.5 Voltsis about 1060 mAh/g. In contrast, as illustrated on FIG. 4, a cell witha CF_(x) electrode exhibits a specific capacity of approximately 860mAh/g. Thus, the Cu_(a)Mn_(b)O_(c) material of the present disclosureprovides an increased specific capacity over devices that includecathodes of CF_(x).

Example 13 End-of-Life Indication

In accordance with various embodiments of the present disclosure, it hasbeen observed that a cathode comprising Cu_(a)Mn_(b)O_(c) may exhibitdischarge characteristics that facilitate end-of-life indication. Forexample, with reference to FIG. 3, after approximately 200 mAh/g, thevoltage output of the cell decreased to a second discharge plateau andremained flat at 2.2V to approximately 700 mAh/g. This second plateaumay advantageously be used in accordance with various aspects of thepresent disclosure to detect the end-of-life of the battery, for examplewhen the cell is approaching the end of the discharge process. Such anend-of-life indication may be desirable in medical device applicationswhere it may be desirable to surgically remove a medical device beforethe battery reaches the end of its lifetime, but not too early duringits lifetime.

Example 14 Rechargeable Battery

In still other embodiments, Cu_(a)Mn_(b)O_(c) may exhibit at leastpartial rechargeability and/or reversibility. FIG. 5 shows cyclicvoltammograms of a Cu_(a)Mn_(b)O_(c) cathode in a pouch cell, indicatinggood reversibility of the cathode over approximately 4.0V to 2.5V. Withreference back to FIG. 3, exemplary embodiments of the presentdisclosure that comprise a Cu_(a)Mn_(b)O_(c) cathode may be reversibleduring the first approximately 200 mAh/g of capacity. Thereafter,exemplary batteries may still comprise a capacity that is substantiallysimilar to electrodes that comprise CF_(x).

Example 15 Electrodes with Cu_(a)Mn_(b)O_(c) and CF_(x)

As previously noted, in one particular embodiment of the presentdisclosure, the cathode material may comprise Cu_(a)Mn_(b)O_(c) combinedwith one or more other cathode materials that have high specificcapacity, such as fluorinated carbon (e.g., CF_(x)). A battery with acathode that comprises Cu_(a)Mn_(b)O_(c) and CF_(x) may exhibit enhancedelectrochemical performance (e.g., specific energy, energy density,operating voltage, and rate capability) relative to a battery withCF_(x) alone. Such a battery may also exhibit a more predictable voltagechange during the last portion of its capacity, thereby producing areliable indicator of the end of its useful life.

In a particular embodiment, Cu_(a)Mn_(b)O_(c) formed according toExample 3 above was mixed with fluorinated carbon, and more specificallyCF_(x) (having the composition CF₁/CF_(0.6), in the ratio of 80/20) toform a cathode. The cathode active part of the blend consisting of 85%(by weight) carbon fluoride and 15% (by weight) Cu_(a)Mn_(b)O_(c) weremixed with Super P and KS4.

The discharge profile of the cell built with the cathode prepared fromthe noted cathode mixture at a discharge rate of 10 mA/g is illustratedin FIG. 4. Discharge data for cells built with carbon fluoride alone asactive are provided in FIG. 4 for comparison. The specific capacity to1.5 Volts of cells built with the admixture of carbon fluoride andCu_(a)Mn_(b)O_(c) as cathode materials is about 1100 mAh/g. Whenevaluated alone, carbon fluoride based cells delivered a specificcapacity to 1.5 Volts of about 820 mAh/g.

It is to be noted that the mixture of 85% CF_(x), having an expectedcapacity of 704 mAh/g, and 15% Cu_(a)Mn_(b)O_(c), having an expectedcapacity of 1060 mAh/g, should have produced a hybrid cathode deliveringa capacity of about 810 mAh/g. The new cathode instead produced anunexpected 36% greater capacity of 1100 mAh/g. The incorporation of theCu_(a)Mn_(b)O_(c) according to embodiments of the present disclosureinto carbon fluoride (or more generally fluorinated carbon) thus led tocells with about 56% capacity improvement, as compared to cells builtwith carbon fluoride alone as cathode active materials.

Example 16 Test Cell

A second exemplary test cell was constructed to further illustrate thecharacteristics of a cathode that comprises Cu_(a)Mn_(b)O_(c), asprepared in Examples 4-10, above. Specifically, an exemplary coin cellbattery, illustrated in FIGS. 9 and 9A, was used as test vehicle (unlessotherwise mentioned) to evaluate the discharge characteristics of acathode that comprises Cu_(a)Mn_(b)O_(c). With reference to FIGS. 9 and9A (FIG. 9A being a cross-section of FIG. 9, along the 9A line), anexemplary test cell comprised a cell can (Y1), a cathode (Y2), aseparator (Y3), a non-aqueous electrolyte, a stainless steel spacer(Y4), a gasket (Y5), a Belleville spring (Y6), a cell cap (Y7) and ananode (Y8). The cell was used either as a rechargeable ornon-rechargeable electrochemical cell. Anode, cathode, separator and theelectrolyte were configured to be contained within cell can and cellcap.

Other electrochemical cells according to various embodiments may be ofany configuration, such as a cylindrical wound cell, a prismatic cell, arigid laminar cell or a flexible pouch, envelope or bag cell.

Example 17 Analysis/Testing of Cu_(a)Mn_(b)O_(c) Using Test Cell

Density measurements for Cu_(a)Mn_(b)O_(c) are shown in FIG. 10. Thedensity of exemplary copper manganese oxide material was found to bebetween about 4.2 to about 5.5 g/cm³. X-ray patterns of 250° C.heat-treated materials of Examples 7, 8, 9 and 10 are illustrated inFIG. 11. As can be seen, there are essentially no sharp peakscharacteristic of crystalline materials. However, two small peaksattributable to CuO were observed for the sample prepared using Example8. The XRD patterns of samples prepared by Examples 8, 9, and 10exhibited a small peak, tentatively attributable to Cu₂O. Thesemi-crystalline nature of the materials of the present disclosuretypically occurs with higher copper content (e.g., 6:1 molar ratio ofCu:Mn). When a low copper content is used (e.g., 1:1 Cu:Mn molar ratio),the resulting material is essentially amorphous, as revealed by XRD.

The surface area of this material was measured by BET method and foundto be about 70 m²/g. Scanning Electron Microscopic images in FIG. 12Aillustrate the particles are in micron size; however, the highermagnification image (insert in FIG. 12A) reveals the nano sizedparticles are agglomerated and form micron size particles. Theagglomerated particles produce a more “pore-like” structure with a highsurface area. FIG. 12B illustrates a SEM image showing two differentfeatures of the surfaces, which are likely to originate from twodifferent components. One component is highly electrically conductive,which is CuO, is darker (arrow indicated in FIG. 12B) and the lowconductive component is likely an amorphous form of manganese oxideand/or copper manganese oxides, which are brighter in the illustratedimage due to their less conductive nature.

FIGS. 13A and 13B illustrates the X-ray Photon Spectroscopy (XPS)results of a sample formed in accordance with Example 7. The detailedpeak analysis of Cu shows two peaks at 934.1 eV and 954.0 eV,attributable to the characteristic binding energy of CuO andCu_(a)Mn_(b)O_(c), respectively. Further, the analysis of manganeseelement shows binding energy peaks at 642.8 and 654.1 eV, belonging tomanganese (IV) oxide (MnO2). The large shoulder in the Mn peak may bedue to part of the materials being in a high oxidation state. Thecalculated metal to oxygen ratio is 0.44, for example; it is well knownthat metal to oxygen ratio of Cu_(a)Mn_(b)O_(c) spinel is 0.6 andCuO/MnO₂ is 0.5. These results suggest that this compound is likely inhigher oxidation state than spinel form of Cu_(a)Mn_(b)O_(c).

In the illustrated cases, the XRD results show that CuO is a semi-and/or crystalline material, whereas manganese oxide and coppermanganese oxide are amorphous. XPS and elemental analysis confirms thecomposition of the materials, which contains Cu, Mn and O. The detailedelemental scan by XPS further indicates the presence of CuO, MnO₂ andCu_(a)Mn_(b)O_(c). High magnification SEM images show the presence ofdifferent elements in the sample. These results suggest that thematerial of the present disclosure exhibits an amorphous and/or asemi-crystalline nature.

FIG. 14 shows the thermal decomposition of copper manganese oxidessynthesized using different molar ratios. The thermal decomposition wasperformed in air at the heating rate of 10° C./min. FIG. 14 shows thatall these materials are thermally stable at 500° C., and the observedweight loss was about 4%, which can be attributed to surface orcrystalline water. When stored, the cathode (made up of the cathodematerial of the present disclosure) in electrolyte (PC/DME/LiBF₄) at 60°C. for 22 days, the average dissolved amount of Cu and Mn is about 5 ppmand 1 ppm, respectively. This data demonstrates good chemical andthermal stability of the materials of various embodiments of the presentdisclosure.

Electrochemical behavior of the cathode material in accordance withvarious embodiments of this disclosure was evaluated in 2325 size coincell using lithium metal as an anode. The cathode consisted of 70%Cu_(a)Mn_(b)O_(c) as the active material, 27% KS4 graphite as conductivefillers, and 3% PTFE as binder. Cu_(a)Mn_(b)O_(c) and KS4 were firstmixed using a mortar and pestle. Then PTFE powder was added to theresulting mix while mixing to form a cathode sheet. The electrode wascut from the resulting sheet with a die. Prior to testing in 2325 sizecoin cells, the cathodes were vacuum dried at 120° C. for about 4 hours.

FIG. 15 shows the discharge profile of the cathode materials of Example10 in a coin cell using lithium metal as an anode. The electrochemicalperformance was measured using a Maccor battery testing system. Thefirst discharge of the cell was at 10 mA/g, down to 2.6 Volts, thesecond at 5 mA/g down to 2.3 Volts, and the third 1 mA/g down to 1.5Volts (signature test). Thus, Cu_(a)Mn_(b)O_(c), according to variousembodiments, exhibited a specific capacity of about 900 mAh/g to about 2Volts, with a plateau to about 2.4 Volts.

In a further embodiment, Cu_(a)Mn_(b)O_(c), was mixed with carbonfluoride (CF₁/CF_(0.6) in the ratio of about 80/20) to form a cathode.The cathode active part of the blend, which included about 90% (byweight) carbon fluoride and 10% (by weight) Cu_(a)Mn_(b)O_(c), was mixedwith carbon black and graphite. (All percents set forth herein are inweight percents, unless otherwise noted.) The investigated cathode wasprepared as described herein above. The discharge profile of the cellbuilt with the resulting cathode, at a discharge rate of 10 mA/g, isillustrated in FIG. 16. Discharge data for cells built with carbonfluoride alone as active are provided in FIG. 16 for comparison. Thespecific capacity to 1.5 Volts of cells built with the admixture ofcarbon fluoride and Cu_(a)Mn_(b)O_(c), in accordance with the presentdisclosure, as cathode materials is about 1007 mAh/g. When evaluatedalone, carbon fluoride based cells delivered a specific capacity to 1.5Volts of about 820 mAh/g.

It is to be noted that the mixture of 90% CF_(x), having an expectedcapacity of about 746 mAh/g, and 10% Cu_(a)Mn_(b)O_(c), having anexpected capacity of about 1000 mAh/g, would be expected to produce ahybrid cathode delivering a capacity of about 846 mAh/g. However, thenew cathode produced an unexpected value of about 19% greater capacityat about 1007 mAh/g. Thus, the incorporation of the Cu_(a)Mn_(b)O_(c)into carbon fluoride, according to various embodiments of the presentdisclosure, thus led to cells with about 35% capacity improvement ascompared to cells built with carbon fluoride alone as cathode activematerials.

Example 18 Internally Rechargeable Battery

As previously noted, cells comprising CF_(x) and the copper manganesemixed oxide of the present disclosure have been observed to exhibit aself-charging capability (i.e., an internal charging or rechargingcapability). Without being held to any particular theory, it is believedthat this is due at least in part to redox reactions involving thedischarge products within the cathode as previously discussed above.FIG. 17 shows the discharge behavior at 3 mA/g of the cell after 5cycles of self-charging. Note that the cell was first discharged using asignature test (i.e., 10 mA/g to 2.5 Volts, 30 mA/g to 2.0 Volts andthen at 1 mA/g). It was then taken out of testing and allowed to restfor about 5 days prior to discharging. While resting, the cell OCV rosefrom about 1.7 Volts to about 2.9 Volts, which suggests an internal- orself-charging process.

FIG. 18 illustrates the voltage profile on ICD test of a pouch cellcomprising CF_(x) and the cathode materials of the present disclosure,Cu_(a)Mn_(b)O_(c). The cathode comprised about 90% CF_(x) and about 10%Cu_(a)Mn_(b)O_(c), by weight. The discharge protocol was as follows:there were four pulses per train in every four hours. The pulseamplitude was calculated by 0.7 A per gram of active materials. As shownin FIG. 18, the voltage dip for the first train of pulses was lessenedor eliminated by incorporating the Cu_(a)Mn_(b)O_(c) material of thepresent disclosure into the cathode. This result suggests that the cellcomprising CF_(x) and the cathode of the present disclosure has a goodrate capability at early stage of discharge compared to cell comprisingCF_(x) without Cu_(a)Mn_(b)O_(c).

When introducing elements of the present disclosure or the preferredembodiments(s) thereof, the articles “a”, “an”, “the” and “said” areintended to mean that there are one or more of the elements. The terms“comprising”, “including” and “having” are intended to be inclusive andmean that there may be additional elements other than the listedelements.

As various changes could be made in the above-described embodiments(e.g., cathode material compositions, electrochemical cell componentsand configurations, etc.) without departing from the scope of thedisclosure, it is intended that all matter contained in the abovedescription and shown in the accompanying figures shall be interpretedas illustrative and not in a limiting sense.

1. A non-aqueous electrochemical cell comprising: an anode; a cathodecomprising a cathode material comprising an amorphous orsemi-crystalline copper manganese oxide cathode material; a separatordisposed between the anode and the cathode; and, a non-aqueouselectrolyte which is in fluid communication with the anode, the cathodeand the separator.
 2. The non-aqueous electrochemical cell of claim 1,wherein the amorphous or semi-crystalline copper manganese oxide cathodematerial has the formula Cu_(a)Mn_(b)O_(c), wherein (i) the coppertherein has an oxidation state between about 1 and about 3, (ii) themanganese therein has an oxidation state between about 2 and about 7,(iii) a and b each have a value greater than zero, and further that thesum of a+b is between about 1 and about 3; and, (iv) c has a value thatmay be experimentally determined and that is consistent with the valuesof a, b and the oxidation states of copper and manganese.
 3. Thenon-aqueous electrochemical cell of claim 1, wherein the amorphous orsemi-crystalline copper manganese oxide cathode material has the formulaCu_(a)Mn_(b)O_(c).nH₂O, wherein (i) the copper therein has an oxidationstate between about 1 and about 3, (ii) the manganese therein has anoxidation state between about 2 and about 7, (iii) a and b each have avalue greater than zero, and further that the sum of a+b is betweenabout 1 and about 3; (iv) c has a value that may be experimentallydetermined and that is consistent with the values of a, b and theoxidation states of copper and manganese; and, (v) “nH₂O” represents thesurface water, the structural water, or both, present in the coppermanganese oxide cathode material.
 4. The non-aqueous electrochemicalcell of claim 1, wherein copper manganese oxide cathode material has anaverage density ranging from about 4 to about 6 g/cm³.
 5. Thenon-aqueous electrochemical cell of claim 1, wherein copper manganeseoxide cathode material has an average density ranging from about 4.5 toabout 5.5 g/cm³.
 6. The non-aqueous electrochemical cell of claim 1,wherein copper manganese oxide cathode material has an average BETsurface area ranging from about 50 to about 150 m²/g.
 7. The non-aqueouselectrochemical cell of claim 1, wherein copper manganese oxide cathodematerial has an average BET surface area ranging from about 75 to about125 m²/g.
 8. The non-aqueous electrochemical cell of claim 1, whereincopper manganese oxide cathode material has an average particle sizeranging from about 10 to about 300 nanometers.
 9. The non-aqueouselectrochemical cell of claim 1, wherein copper manganese oxide cathodematerial is amorphous, the copper and manganese being present therein inan average molar ratio of about 1:1 to less than 3:1 (Cu:Mn).
 10. Thenon-aqueous electrochemical cell of claim 1, wherein the coppermanganese oxide is semi-crystalline, the copper and manganese beingpresent therein in an average molar ratio of 3:1 to about 6:1 (Cu:Mn).11. The non-aqueous electrochemical cell of claim 1, wherein coppermanganese oxide cathode material is in the form of agglomeratedparticles, the agglomerated particles having an average agglomeratedparticle size of from about 5 to about 45 microns.
 12. The non-aqueouselectrochemical cell of claim 1, wherein the cathode materialadditionally comprises fluorinated carbon.
 13. The non-aqueouselectrochemical cell of claim 12, wherein the fluorinated carbon has theformula CF_(x), wherein x is about 0.1 to about 1.9.
 14. The non-aqueouselectrochemical cell of claim 13, wherein the concentration of coppermanganese oxide in the cathode material is between about 1 wt % andabout 99 wt %, and the concentration of fluorinated carbon in thecathode material is between about 99 wt % and about 1 wt %.
 15. Thenon-aqueous electrochemical cell of claim 12, wherein the fluorinatedcarbon is a mixture of materials having the formulas (CF_(x1))n and(CF_(x2))m, wherein x1 is about 0.8 to about 1.2, x2 is about 0.4 toabout 0.8, n is about 1 to about 5, and m is about 1 to about
 5. 16. Thenon-aqueous electrochemical cell of claim 15, wherein the concentrationof copper manganese oxide in the cathode material is between about 1 wt% and about 99 wt %, and the concentration of fluorinated carbon in thecathode material is between about 99 wt % and about 1 wt %.
 17. Thenon-aqueous electrochemical cell of claim 1, wherein the non-aqueouselectrolyte comprises an organic solvent selected from the groupconsisting of dimethyl carbonate (DMC), diethyl carbonate,1,2-dimethoxyethane (DME), tetrahydrofuran (THF), methyl acetate (MA),diglyme, trigylme, tetragylme, propylene carbonate (PC), ethylenecarbonate (EC), acetonitrile, dimethyl sulfoxide, dimethyl formamide,dimethyl acetamide, gamma-butyrolactone (GBL), andN-methyl-pyrrolidinone (NMP), or a mixture of two or more thereof. 18.The non-aqueous electrochemical cell of claim 17, wherein thenon-aqueous electrolyte comprises a salt having a formula MM′F₆ orMM′F₄, wherein M is an alkali metal that is the same as at least one ofthe metals in the anode and M′ is an element selected from the groupconsisting of phosphorous, arsenic, antimony and boron.
 19. Thenon-aqueous electrochemical cell of claim 18, wherein the salt isselected from the group consisting of LiPF₆, LiAsF₆, LiSbF₆, LiBF₄,LiClO₄, LiAlCl₄, LiGaCl₄, LiC(SO₂CF₃)₃, LiB(C₆H₄O₂)₂, LiN(CF₃SO₂)₂ andLi(CF₃SO₃), as well as mixtures thereof.
 20. The non-aqueouselectrochemical cell of claim 18, wherein the non-aqueous electrolytecomprises a salt, the concentration of the salt in the organic solventbeing in the range of between about 0.5 M and about 2.5 M.
 21. Thenon-aqueous electrochemical cell of claim 1, wherein the anode comprisesa metal selected from Group IA or Group IIA of the Periodic Table of theElements.
 22. The non-aqueous electrochemical cell of claim 21, whereinthe anode comprises a metal selected from the group consisting oflithium, magnesium, sodium, potassium.
 23. The non-aqueouselectrochemical cell of claim 22, wherein the anode comprises an alloyor intermetallic compounds selected from the group consisting of Li—Mg,Li—Al, Li—Al—Mg, Li—Si, Li—B and Li—Si—B.
 24. The non-aqueouselectrochemical cell of claim 1, wherein the cathode materialadditionally comprises fluorinated carbon, and further wherein the cellexhibits an end-of-life indication comprising a voltage plateau of about2 to about 2.4 volts.